ci: [stable-8.2] cancel superseded PR runs and cap matrix parallelism

.github/workflows/acceptance-tests.yml

@@ -4,6 +4,12 @@ on:
   pull_request:
   workflow_dispatch:
 
+# Pull request runs cancel their predecessor on the same PR. Every other
+# event gets its own group, so pushes and scheduled runs never cancel each other.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   detect-changes:
     name: detect-changes
@@ -173,6 +179,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
+      max-parallel: 8
       matrix:
         suite:
           # contract & locks
@@ -356,6 +363,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
+      max-parallel: 4
       matrix:
         suite:
           - "coreApiAuth,coreApiCapabilities,coreApiFavorites,coreApiMain,coreApiVersions"
@@ -439,6 +447,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
+      max-parallel: 4
       matrix:
         include:
           - suite: part-1

.github/workflows/check-licenses.yml

@@ -4,6 +4,12 @@ on:
   push:
     branches: [master, stable-*]
 
+# Pull request runs cancel their predecessor on the same PR. Every other
+# event gets its own group, so pushes and scheduled runs never cancel each other.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   license-check:
     runs-on: ubuntu-latest

.github/workflows/web-tests.yml

@@ -5,6 +5,12 @@ on:
   push:
     branches: [master, stable-*]
 
+# Pull request runs cancel their predecessor on the same PR. Every other
+# event gets its own group, so pushes and scheduled runs never cancel each other.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
 jobs:
   detect-web-changes:
     name: detect-web-changes